The objective is to determine the optimal means of detection, incidence, etiology, clinical and laboratory features, and effects of treatment of human zinc deficiency in the pregnant and lactating woman, premature and term infant, and growing child. Individual protocols include: 1) A randomized, double-blind controlled study of dietary zinc supplmentatiion throughout lactation to determine the effects on maternal zinc status, milk zinc concentration, volume of milk consumed by the breast fed infant, zinc status of the breast fed infant, and growth velocity of the breast fed infant; 2) Randomized, double-blind controlled studies of dietary zinc supplementation throughout pregnancy to determine the effects on biochemical indices of zinc status, obstetric outcome, fetal development and early post-natal course. Additional studies during pregnancy will be undertaken to determine the effects of routine antenatal iron supplements on maternal zinc status; to determine maternal zinc status in type I diabetes mellitus throughout pregnancy; and to investigate maternal zinc status pre- and post-conception in cases of recurrent, neural tube defects. 3) The effects of zinc supplementation on net zinc absorption and zinc balance in very low birth weight premature infants fed with their own mother's fresh or fresh-frozen milk. Fractional absorption and endogenous fecal zinc losses will also be calculated utilizing fast atom bombardment/mass spectrometry zinc stable isotope methodology. 4) The effects of small dietary zinc supplements on infants and toddlers with unexplained failure to thrive under carefully controlled conditions. 5) The investigation of zinc nutriture and zinc metabolism in selected disease states including sickle cell disease, acrodermatitis enteropathica, chronic obstructive neonatal liver disease, and pyoderma gangrenosum. 6) The development and evaluation of additional laboratory tools for the assessment of human zinc nutriture, including the provision of essential support for the development of zinc stable isotope techniques.